Gas-powered appliances typically have some control system included for controlling the operation of the appliance. In this context, a gas-powered appliance may be a water heater, a fireplace insert, a furnace, a gas stove, or any other gas-powered appliance. Also in this context, “gas-powered” typically means that natural gas or liquid propane gas is used as a primary fuel source, but it should be recognized that “gas powered” may also include any other suitable fuel source either in a liquid or gaseous state, as desired.
In a fuel-fired, storage-type water heater, for example, a combustion chamber and an air plenum are typically disposed below or near a water tank. A burner element, fuel manifold tube, ignition source, thermocouple, and a pilot tube typically extend into the combustion chamber. When the temperature of the water in the tank falls below a set minimum, fuel is introduced into the combustion chamber through the fuel manifold tube and burner element. This fuel is ignited by the pilot flame or other ignition source, and the flame is maintained around the burner element. Air is drawn into the plenum, sometimes assisted by a blower, and the air mixes with the fuel to support combustion within the combustion chamber. The products of combustion typically flow through a flue or heat exchange tube in the water tank to heat the water by convection and conduction.
Gas valves used in conjunction with gas-powered appliances are known. These gas valves are typically controlled by one or more magnetic or piezoelectric control valves. However, magnetic valves often require a relatively large amount of power to operate, and are bulky. Piezoelectric valves are often relatively expensive, unreliable over an operating temperature from, for example, −30 to 85 degrees Celsius, and often do not provide a desired displacement for optimal performance. Thus, alternative gas valves are sought.